The purpose of this investigation is to improve understanding of the effects of children's direct exposure to 9/11 and future mental health disorders, substance use or abuse and other risky behaviors as they now enter into adolescence and emerging adulthood. Based on the behavioral development literature, our city-wide assessment of children 6 months after 9/11 and the numerous findings of post- 9/11 consequences amidst exposed adults, there is strong evidence to suggest that exposure to 9/11 early in life would increase directly exposed children's vulnerability within the domains of interet in this investigation. Unfortunately, to date, the science-base of post-disaster behavioral consequences for youth, including those who were 9/11 exposed as children, lacks a longitudinal assessment, that includes in-depth measurement of the multiple, complex relevant domains, from type and severity of exposure to well-defined behavioral outcomes and intrapersonal, familial, academic and environmental factors. The proposed study will assess 1,000 children directly exposed to 9/11 at ages 0-12 and currently ages 12- 24, drawn from the World Trade Center Health Registry (WTCHR) Pediatric sample, who will be compared to unexposed Controls (N=500). The study involves a synergistic collaboration between the Child Psychiatric Epidemiology Group (CPEG) at Columbia University-Research Foundation for Mental Hygiene and the WTCHR. The WTCHR has longitudinal data on this population since 2002-2003, including excellent participant tracking information. CPEG has conducted many large-scale assessments of vulnerable youth, including 9/11 exposed children and their parents, addressing themes of high public health relevance. The proposed study will build upon ongoing research, as CPEG has a successful collaboration with the WTCHR, focused on children's whose parents were exposed to 9/11. Using a combination of well-tested epidemiologic methods, augmented by the original consideration of behavioral decision making assessments, findings from this study will fill important knowledge gaps which could significantly reduce the potential burden of lifetime behavioral problems and disabilities, by facilitating diagnosis interventions geared towards 9/11 exposed youth and potentially other disaster exposed populations.